The present invention is directed to PCR sample preparation, particularly to the manipulation of particle in a sample fluid using dielectrophoretic forces to concentrate and move samples in an electrophoretic channel, and more particularly to movement of particles by sequentially activated/deactivated electrodes position along a length of a channel.
Extensive efforts are being carried out to enable sample preparation for various amplication, such as to provide PCR sample preparation for counter biological warfare applications, as well as for a clinical tool to determine genetic information. A key element of the sample preparation process is to enable controlled concentration and/or movement of DNA, for example, prior to detection.
The present invention enables manipulation of DNA and cells/spores using dielectrophoretic (DEP) forces to perform sample preparation protocols for polymerized chain reaction (PCR) based assays. The invention utilizes a series of electrodes located along a length of an electrophoretic channel. Since DEP forces induce a dipole in the sample particles, these particles can be trapped in non-uniform fields produced by electrodes located along a length of the channel. By switching on and off sequentially located electrodes, the electric field s produced thereby cause the particles to be moved down a channel and/or concentrated in the channel, with little or no flow. Thus, the invention provides movement of particles using sequentially activated dielectrophoretic particle trapping.
It is an object of the present invention to provide movement and concentration of particles in an electrophoretic channel.
A further object of the invention is to provide movement of particles using sequentially activated dielectrophoretic particle trapping.
A further object of the invention is to enable manipulation of DNA and cells/spores using dielectrophoretic forces to perform sample preparation protocols for PCR based assays.
Another object of the invention is to provide an electrophoretic channel with sets of electrodes, which can be sequentially activated to cause movement of particles down the channel.
Another object of the invention is to photolithographically pattern electrodes along a length of dielectrophoretic channel, whereby controlled activation/deactivation of the various electrodes enable concentration of or movement of the particles with little or no sample fluid flow.
Another object of the invention is to provide an electrophoretic channel with sets of electrodes located along a length or the channel whereby particles can be trapped in the high electric field strength produced by the electrodes, and sequential activation/deactivation of those electric field cause movement of the particles down the channel.
Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings. Basically the present invention provides for movement of particles using dielectrophoretic (DEP) forces. The particles are moved using sequentially activated dielectrophoretic particle trapping. The sequential particle trapping is carried out by sets of electrodes located along a length of an electrophoretic channel, and subsequent adjacent electrodes are activated to cause the movement of the particles down the channel. The electrodes may be photolithographically patterned on the bottom and the top of the flow channel, with a number of electrode segments on either the top or bottom with a single electrode on the respective bottom or top of the channel. An alternating current (AC) signal is placed between an electrode segment and the opposite electrode to produce an electric field which traps the charged particles due to the dielectrophoretic forces imposed thereon. Switching of the AC signal from an electrode segment to a downstream electrode segment results the particles being drawn downstream by the changing electric fields. By control of the AC signal on the electrodes, the particles can be collected at any desired point in the channel or movement along the channel as need for PCR assays, for example.